To match the change in PDC_scr_open(), free SP in delscreen() rather

than PDC_scr_free().

docs/IMPLEMNT.md

@@ -246,8 +246,7 @@ the cursor to the lower left corner. (The X11 port does nothing.)
 
 ### void PDC_scr_free(void);
 
-Frees the memory for SP allocated by PDC_scr_open(). Called by
-delscreen().
+Free any memory allocated by PDC_scr_open(). Called by delscreen().
 
 ### int PDC_scr_open(int argc, char **argv);
 

dos/pdcscrn.c

@@ -479,8 +479,6 @@ void PDC_scr_close(void)
 
 void PDC_scr_free(void)
 {
-    if (SP)
-        free(SP);
 }
 
 /* open the physical screen -- miscellaneous initialization, may save

os2/pdcscrn.c

@@ -79,8 +79,6 @@ void PDC_scr_close(void)
 
 void PDC_scr_free(void)
 {
-    if (SP)
-        free(SP);
 }
 
 /* open the physical screen -- miscellaneous initialization, may save

pdcurses/initscr.c

@@ -294,7 +294,7 @@ void delscreen(SCREEN *sp)
 {
     PDC_LOG(("delscreen() - called\n"));
 
-    if (sp != SP)
+    if (!SP || sp != SP)
         return;
 
     PDC_slk_free();     /* free the soft label keys, if needed */
@@ -308,8 +308,9 @@ void delscreen(SCREEN *sp)
 
     SP->alive = FALSE;
 
-    PDC_scr_free();     /* free SP */
+    PDC_scr_free();
 
+    free(SP);
     SP = (SCREEN *)NULL;
 }
 

sdl1/pdcscrn.c

@@ -83,8 +83,6 @@ void PDC_scr_close(void)
 
 void PDC_scr_free(void)
 {
-    if (SP)
-        free(SP);
 }
 
 static void _initialize_colors(void)

sdl2/pdcscrn.c

@@ -93,8 +93,6 @@ void PDC_scr_close(void)
 
 void PDC_scr_free(void)
 {
-    if (SP)
-        free(SP);
 }
 
 static void _initialize_colors(void)

wincon/pdcscrn.c

@@ -359,9 +359,6 @@ void PDC_scr_close(void)
 
 void PDC_scr_free(void)
 {
-    if (SP)
-        free(SP);
-
     if (pdc_con_out != std_con_out)
     {
         CloseHandle(pdc_con_out);

x11/pdcscrn.c

@@ -170,12 +170,6 @@ void PDC_scr_close(void)
 
 void PDC_scr_free(void)
 {
-    if (!SP)
-        return;
-
-    free(SP);
-    SP = NULL;
-
     if (icon_pixmap)
         XFreePixmap(XCURSESDISPLAY, icon_pixmap);
     if (icon_pixmap_mask)